The present invention relates to a negative film masking system attachable to a negative film masking mount at the printing station of a known photographic processing and printing machine.
Such a negative film masking system in the photographic processing and printing machine is designed such that while a negative film loaded in a negative film masking assembly is advanced frame by frame, a desired frame of the negative film is halted at a location in alignment with a four-sided film gate aperture (at an exposure location) of the masking assembly and is exposed to produce a print on a sensitized paper and is securely held down by a film hold-down of the masking assembly.
A common photographic negative film of 135 roll or piece form contains standard size frames and panoramic size frames in random combination. Hence, printing of an image of the panoramic size requires the use of a specific mask having a film gate aperture which is identical in size to the panoramic frame.
The use of such a specific mask is essential to measure the transmission of light through the frame with LATD sensors which will be described later. If a portion of light transmitted through unexposed regions of the film is detected, it interrupts correct measurement.
It is a good idea to have the masking system provided with a detector capable of automatically distinguishing a panoramic size frame from a standard size frame on a negative film for ease of printing operation. Although the masking system with such a detector allows the operator to perform a printing operation with ease, the cost of production will be high.
If no such detector is provided with the masking system, the operator has to check a negative film visually for panoramic frames and remember or record the location of such frames to be printed prior to loading the film to the masking system.
The memorization or recording of the location of panoramic frames of the negative film is however troublesome, demanding an extra step in the printing operation. Also, if any panoramic frame is incorrectly recognized or recorded as being of the standard size, it will be exposed in the standard size film gate aperture of the mask, thus causing the processing and printing machine to lose its exposure control.
It is an object of the present invention, in view of the foregoing, to provide a negative film masking system for use in a photographic processing and printing machine, wherein each desired panoramic frame on a negative film loaded in a negative film masking assembly is visibly identified when it is located at the exposure location or one frame before the same, so that exposure through the panoramic size film gate aperture of the masking assembly can successfully be carried out without memorizing or recording the location of the panoramic frames.